A summary thread on lighting

[Ross]

Originally Posted by Sandy4453

So......do you happen to know how to install lights on a screened patio that loses light in winter, without getting electrocuted when it rains?

Check out this product 48" GLO Dual T5 HO 2 x 54W Lighting System by Hagen - AquaCave I use the 24" version of this in an installation where I gett water dripping on it. It's totally safe for aquarium use and comes with special caps that seal the contacts at the ends of the tubes. Rather pricy, but you get what you pay for. If I were going outdoors with supplemental lighting, I'd consider this fixture. Another option might be Metal Halide hot lights, but there is way more potential for water damage. Be sure to have a ground-fault-interupter (GFI) cicuit specifically for these fixtures. That will aid to safety as well as assure zoning complience.

[judygrove]

Hi Ross, Thanks for all the information you have provided on indoor lighting for the orchids. I have done a lot of research but still remain confused on one issue. My light meter reads in lux. I understand that I need to divide that reading by 10.76 in order to get approximate foot candles. That part is scientific fact. Then how do I get 1000 foot candles (low light for orchids) when there isn't a regular gro-light or flourescent or even the full sun bulbs which will accomplish that. Even in direct sun you have 6000 lux or approximately 558 foot candles. I am wondering if all these charts stating foot candles really mean lux. I know square footage and reflectors on the bulbs play a role but it still doesn't get the foot candles high enough.

Thanks for your help.
Judy

[Ross]

Originally Posted by judygrove

Hi Ross, Thanks for all the information you have provided on indoor lighting for the orchids. I have done a lot of research but still remain confused on one issue. My light meter reads in lux. I understand that I need to divide that reading by 10.76 in order to get approximate foot candles. That part is scientific fact. Then how do I get 1000 foot candles (low light for orchids) when there isn't a regular gro-light or flourescent or even the full sun bulbs which will accomplish that. Even in direct sun you have 6000 lux or approximately 558 foot candles. I am wondering if all these charts stating foot candles really mean lux. I know square footage and reflectors on the bulbs play a role but it still doesn't get the foot candles high enough.

Thanks for your help.
Judy

Judy, something sounds wrong here. In full sun you should be seeing nearly 4000 foot-candles (do conversion for Lux - I'm at a guest computer right now.) If you are reading less than that then there must be a scale factor you need to apply. Also 1000 foot-candles is only low for certain orchids. Paphs, Phrags, Phals, etc. all can thrive at less than this level but prefer 1000-1500 FCs. Foot candles are not Lux. Lux is a universal measurement used by places outside North America. In North America we tend to prefer foot-candles. Hope this helps. PM me if you have specific questions not addressed here.

[squillae]

I just bought my first orchids and so have little info of merit to add to this thread except to point out a gap in our thinking. Consider: anyone who has read a little will learn that Metal Halide verus Sodium is preferred for vegetative versus flowering, respectively. Have I missed something? Can fluorescent light sources do both at once? I've read a bunch of books and blogs and don't think anyone has done a good job anwering this fundamental question: should you provide different light to an orchid at different periods in its lifecycle to promote flowering?

Perhaps orchids don't respond to natural changes in light as the seasons progress. Otherwise how can fluorescents be a "preferred" source if there is no way of 'mixing' the wavelengths. There seems no option here if you want to leave the rest period and initiate a flowering period.
We learn from reading that cycling the temperature lower is the most powerful determinant for initiating flowering in orchids...i think. Hmm, do orchids have a photoperiod and, if so, should we factor that in when selecting how to grow our orchids indoors away from the window?
If there is someone who can reference my silly question I'd be happy to read/research more on this point.

[johnblagg]

Execellent post Ross and deserves a sticky for sure ....from all my reseach the 600 watt Mh is the most effecient light available for lumens produced per watt .

[Paul Mc]

Thank you so much for this thread! I will come back and read this tonight!

[Ray]

Lighting has SO many variables, it drives me nuts. For example:

Originally Posted by johnblagg

....from all my reseach the 600 watt Mh is the most effecient light available for lumens produced per watt .

Metal halides do put out about 125 lumens per watt, second only to high pressure sodium bulbs at 140. Unfortunately, between the heat generation and the emitted spectrum, a lot of the benefit is lost - that is, not all of the lumens are in the wavelengths they need to be.

(I'll ignore the measurement units, showing only the relative levels.) A MH bulb, typically around 4000°K color temperature, for example, has (roughly) an energy intensity of 5 units in the blue end, and about 12.5 in the red end. A HO T5 bulb, on the other hand, with a 6400°K color temperature, puts out about 100 and 90, respectively. (Which may - to some extent - explain the purple coloration at lower foot-candles than full sun.)

Amazing as it seems to me, and HPS bulb - as bright as they may be - puts out essentially no light in the blue end and about 1000x less in the red end than does that T5 bulb.

[jebar77]

i have 2 400w mh fixtures plus a T8 fixture over everything. i believe i have a 10k, 6500k mh bulbs and im not sure about the t8 bulbs .... they are the run of the mill lowes replacement bulbs for the fixture, for me i need the extra heat during the winter months, all my plants are in the basement and i dont want to use the forced hot air to warm the plants and dry them out... even during the summer months i like to have the heat from the fixtures because the basement still stays a bit cooler than the outside.

[Becka]

Can I use any CFL to provide light to my orchids? What about a CFL that provides light for reptiles?

I am looking for a non-expensive set-up to supplement the natural light my orchids receive.

[Magnus A]

Originally Posted by Becka

Can I use any CFL to provide light to my orchids? What about a CFL that provides light for reptiles?

I am looking for a non-expensive set-up to supplement the natural light my orchids receive.

Yes you can!

Go for a "full Spectrum" bulb at a color temperature around 4000-6500 Kelvin.
Do not bother for special lampsfor reptiles as they usually give "alot" NIR-light (near infra red). I would neither bother about special plant lamps as the light look terribly and the cost is much higher without beeing sufficient better!


Some information:
There is nothing called "degree Kelvin" (°K), you do not use "degree" when measuring Kelvin temperatures. You though do when you talk about degree Celsius (°C).

/M